Conventionally, in a storage device, port control logic circuits (5031 to 5034) of respective ports (ports 0 to 3) and drivers (5051 to 5054), all of which are mounted on a disk control substrate 501, and receiver drivers (5151 to 5154) and port control circuits (5171 to 5174), all of which are mounted on respective disk drive substrates (5131 to 5134) on respective backboards (5111 to 5114) of a disk drive unit 5091, are connected by respective port-control signal cables (5071 to 5074), as shown in FIG. 1. Further, respective port control logic circuits (5031 to 5034) and respective drivers (5051 to 5054), receiver drivers (5211 to 5214) and port control circuits 5231 to 5234), all of which are mounted on respective disk drive substrates (5191 to 5194) on respective backboards (5111 to 5114) of a disk drive unit 5092, are connected via drivers (5251 to 5254) and separate port control signal cables (5271 to 5274), all of which are mounted on respective disk drive substrates (5191 to 5194). Further, as shown in FIG. 2(a), four of each of an FC signal connector 529 and a port control signal connector 531 are arranged alternately along one edge of the disk control substrate 501.
Furthermore, in the case of the conventional storage device detailed above, a plurality (two in FIG. 3) of disk control substrates 5531, 5532 are mounted in the disk control unit 551, as shown in FIG. 3, and a total of eight port control logic/FC control logic circuits (5551 to 5558) are mounted on each of the disk control substrates (5531, 5532) respectively so that there are four ports on each substrate. Next, the respective port control logic/FC control logic circuits (5551 to 5558) and individual disk drive substrates (5611 to 5618), which are arranged on respective backboards (5591 to 5594) in a disk drive unit 557, are connected by two types of cable, which are Fiber Channel Interface FC signal cables (hereinafter abbreviated to ‘FC signal cables’) (5631 to 5638) and port control signal cables (5651 to 5658). Here, the port control signal cables (5651 to 5658) are cables for transmitting logic level signals required for controlling and monitoring the Fiber Channel Interface LSI and logic level signals required for monitoring the fault status of the parts and power supplies that constitute the disk drive unit 557.
However, in the case of the storage device with the above constitution, the width region (mounting width) on the disk control substrate 501 that is required to connect the port control signal cables (5651 to 5658), which is occupied by a plurality (four in FIG. 2) of port control signal connectors (531) that are arranged in a row on the disk control substrate 501, is approximately 50 mm and comparatively large, as shown in FIG. 2(b). For this reason, when port control signal connectors (531) for four ports are mounted on the same disk control substrate 501, substantially the whole edge of the disk control substrate 501 is then used. This is because a space of about 32 mm is required in order to move a pair of connector lock levers 531a of the port control signal connector (531) shown in FIG. 2(b) along the surface of the disk control substrate 501 when attaching or detaching the port control signal cables (5651 to 5658). Therefore, the number of respective port control logic/FC control logic circuits (5551 to 5558) mounted on the respective control substrates 501 is subject to restrictions and, hence, the mount number of the port control logic/FC control logic circuits (5551 to 5558) cannot be increased by exceeding the restricted number.
In addition, in the case of the storage device with the above constitution, port control signal cables (5651 to 5658), which connect the respective port control logic/FC control logic circuits (5551 to 5558) and the disk drive substrates (5611 to 5618) (mounted on the disk drive unit 557), are required for each port, and each port control signal cable (5651 to 5658) is wired on each disk drive substrate (5611 to 5618). Moreover, when the mount number of HDD (hard disk drives) is maximized in the disk drive unit 557, the disk drive substrates (5611 to 5618) and HDD are mounted with high density. Therefore, the distance between the respective disk drive substrates (5611 to 5618) is then short, meaning that the port control signal cables (5651 to 5658) and FC signal cables (5631 to 5638) are intertwined within a short interval. As a result, the port control signal cable of port 0, for example, is wrongly connected to the connector of another port, which means the problems of the device not operating normally readily occurs.
As is clear from the above description, conventionally, the number of port control logic/FC control logic circuits (5551 to 5558) that can be mounted on the disk control substrate (501) is restricted by the port control signal connectors, and, even with high integration of the port control logic/FC control logic circuits (FC control logic control LSI) (5551 to 5558) mounted on the disk control substrate (501), there is the problem that the number of controlled ports cannot be increased. In addition, because, in the disk drive unit (557), the same cables are wired in very close positions in accordance with the increase in the number of cables and the high density mounting, there is the problem that, as described above, an erroneous connection is easily made. Further, within a storage device with an increased number of connected cables, a space for wiring and fixing the cables is required, and there is therefore the problem that the storage device cannot be miniaturized. Further, there is also the problem that it is difficult to reduce the costs of the storage device due to the above-mentioned problems.